Tetrasaccharide iteration synthesis of a heparin-like dodecasaccharide and radiolabelling for in vivo tissue distribution studies

Abstract

Heparin-like oligosaccharides mediate numerous important biological interactions, of which many are implicated in various diseases. Synthetic improvements are central to the development of such oligosaccharides as therapeutics and, in addition, there are no methods to elucidate the pharmacokinetics of structurally defined heparin-like oligosaccharides. Here we report an efficient two-cycle [4+4+4] tetrasaccharide-iteration-based approach for rapid chemical synthesis of a structurally defined heparin-related dodecasaccharide, combined with the incorporation of a latent aldehyde tag, unmasked in the final step of chemical synthesis, providing a generic end group for labelling/conjugation. We exploit this latent aldehyde tag for 3H radiolabelling to provide the first example of this kind of agent for monitoring in vivo tissue distribution and in vivo stability of a biologically active, structurally defined heparin related dodecasaccharide. Such studies are critical for the development of related saccharide therapeutics, and the data here establish that a biologically active, synthetic, heparin-like dodecasaccharide provides good organ distribution, and serum lifetimes relevant to developing future oligosaccharide therapeutics.

Synthesis of 3-O-Sulfated Oligosaccharides to Understand the Relationship between Structures and Functions of Heparan Sulfate

“…A number of oligosaccharides are synthesized via a purely organic synthetic approach 11–15 , but it is still very difficult to synthesize oligosaccharides larger than hexasaccharides with complex sulfation patterns. As an alternative approach, a chemoenzymatic method to synthesize HS oligosaccharides has emerged, using HS biosynthetic enzymes involving glycosyltransferases, C 5 -epimerase, and sulfotransferases 16–17 .…”

Pharmacology of Heparin and Related Drugs

“…The Pharmacology of Heparin and Related Drugs scale on which heparin-like molecules can be synthesized has been a particular challenge. Another synthetic strategy has proved capable of delivering grams of synthetic heparin oligosaccharides by an iterative procedure using disaccharide (Hansen et al, 2013a,b) or tetrasaccharide (Hansen et al, 2013a) building blocks. The enabling technology in this strategy was the development of plentiful iduronate-containing precursors (Hansen et al, 2012).…”

Chemical Synthesis of Syndecan‐3 Glycopeptides Bearing Two Heparan Sulfate Glycan Chains

“…In sharp contrast to peptides bearing N ‐glycans and mucin type O ‐glycans, glycosaminoglycan glycopeptide syntheses are much less developed, despite the ubiquitous presence and many important biological functions of this class of glycans 6. Synthesis in this area has mainly focused on the glycosaminoglycan oligosaccharides7–23 or the tetrasaccharide linker 24–27. Recently, we reported the first synthesis of a proteoglycan family glycopeptide; a syndecan‐1 glycopeptide bearing one heparan sulfate chain 28.…”